This invention relates generally to a hand tool or a bar clamp of the type used to temporarily clamp together two articles, for example, for gluing, or to hold a workpiece for welding, and more particularly to a quick-action bar clamp wherein the moving jaw can be rapidly advanced or advances in small increments of selectable length.
Alternatively, the hand tool of the invention can be used as a spreader to spread apart elements of the same article or two separate articles. Rapid advancement of the movable jaw and firm grip makes it possible to use the hand tool as a wrench or a cutter.
In recent years, over-center toggle action handgrips have been incorporated for use in final tightening against the workpiece, for example, in U.S. Pat. Nos. 4,088,313 by Pearson and 4,563,921 by Wallace. A disadvantage in the prior art lies in the fact that adjustment in the moving jaw is cumbersome and imprecise. Frequently, the moving jaw is entirely disengaged and free to move until the final tightening of an object between the movable and fixed jaws is accomplished.
What is needed is a versatile hand tool having a moving jaw which is rapidly movable over distances to engage a workpiece and is operable using one hand with complete control by the operator at all times.